Abstract: The interaction of 4′-O-(α-L-oleandrosyl)daunorubicin(ODNR) with calf thymus DNA(ctDNA) in Tris-HCl buffer solution(pH=7.4) was studied by fluorescence and ultraviolet absorption spectroscopies. Effects of the ionic strength, KI quenching, and the ODNR binding differences between the single stranded DNA(ssDNA) and the double stranded DNA(dsDNA) were studied. The results showed that the major binding mode between ODNR and ctDNA was intercalation. The intrinsic fluorescence of ODNR was quenched by ctDNA through static quenching procedure. The binding constants(K) and sites(n) at different temperatures were obtained by Scatchard equation. The predominant intermolecular forces are likely the hydrophobic and electrostatic interactions according to the thermodynamic parameters.

Key words: ODNR, ctDNA, Interaction, Fluorescence spectrum, Intercalative binding